/* 1.高精度加法 2.高精度减法 3.高精度乘法 4.高精度除以低精度 5.高精度对低精度的取余 必要时可以将全局的int替换成long long.除了main函数的返回值int 用到除法和取余的时候可能需要把全局的int替换成long long */ #include <cstdio> #include <iostream> #include <cstring> #include <climits> using namespace std; #define maxn 30000 struct bign { int len, s[maxn]; bign() { memset(s, 0, sizeof(s)); len = 1; } bign(int num) { *this = num; } bign(const char* num) { *this = num; } bign operator = (int num) { char s[maxn]; sprintf(s, "%d", num); *this = s; return *this; } bign operator = (const char* num) { len = strlen(num); for (int i = 0; i < len; i++) s[i] = num[len-i-1] - '0'; return *this; } string str() const { string res = ""; for (int i = 0; i < len; i++) res = (char)(s[i] + '0') + res; if (res == "") res = "0"; return res; } /*去除前导0*/ void clean() { while(len > 1 && !s[len-1]) len--; } /*高精度的加法*/ bign operator + (const bign& b) const { bign c; c.len = 0; for (int i = 0, g = 0; g || i < max(len, b.len); i++) { int x = g; if (i < len) x += s[i]; if (i < b.len) x += b.s[i]; c.s[c.len++] = x % 10; g = x / 10; } return c; } /*高精度的减法*/ bign operator - (const bign& b) { bign c; c.len = 0; for (int i = 0, g = 0; i < len; i++) { int x = s[i] - g; if (i < b.len) x -= b.s[i]; if (x >= 0) g = 0; else { g = 1; x += 10; } c.s[c.len++] = x; } c.clean(); return c; } /*高精度的乘法*/ bign operator * (const bign& b) { bign c; c.len = len + b.len; for (int i = 0; i < len; i++) for (int j = 0; j < b.len; j++) c.s[i+j] += s[i] * b.s[j]; for (int i = 0; i < c.len-1; i++) { c.s[i+1] += c.s[i] / 10; c.s[i] %= 10; } c.clean(); return c; } /*高精度除以低精度*/ /*用到除法和取余的时候可能需要把全局的int替换成long long*/ bign operator / (long long b) const { assert(b > 0); bign c;c.len = len; for (long long i = len-1, g = 0; i >= 0; --i) { long long x = 10*g+s[i]; //这里可能会超过int 故用long long c.s[i] = x/b; //这里可能会超过int g = x-c.s[i]*b; //这里可能会超过int } c.clean(); return c; } /*高精度对低精度取余*/ /*用到除法和取余的时候可能需要把全局的int替换成long long*/ bign operator % (long long b) { assert(b > 0); bign d = b; bign c = *this-*this/b*d; return c; } bool operator < (const bign& b) const { if (len != b.len) return len < b.len; for (int i = len-1; i >= 0; i--) if (s[i] != b.s[i]) return s[i] < b.s[i]; return false; } bool operator > (const bign& b) const { return b < *this; } bool operator <= (const bign& b) { return !(b > *this); } bool operator >= (const bign& b) { return !(b < *this); } bool operator == (const bign& b) { return !(b < *this) && !(*this < b); } bool operator != (const bign& b) { return (b < *this) || (*this < b); } bign operator += (const bign& b) { *this = *this + b; return *this; } }; istream& operator >> (istream &in, bign& x) { string s; in >> s; x = s.c_str(); return in; } ostream& operator << (ostream &out, const bign& x) { out << x.str(); return out; }